The present invention is directed, in general, to communications systems and, more specifically, to controlling the routing of data packets through a xe2x80x9cconnectionlessxe2x80x9d packet-switched network, without bearer channel control signaling.
Conventional communications networks, such as the Public Switched Telephone Network (PSTN), are xe2x80x9cconnection-orientedxe2x80x9d networks; connection-oriented networks require a bearer channel to be established between a sending node and a receiving node before any messages are transmitted therebetween. The PSTN utilizes the Signaling System 7 (SS7) control signaling, including the Integrated Services Digital Network (ISDN) User Part (ISUP), to establish such bearer channels; ISUP defines the protocol and procedures used to set-up, manage, and release trunk circuits that carry voice and data calls over the PSTN.
In recent years there has begun a convergence of communications networks, including the use of the public Internet for the transmission of voice calls historically carried by the PSTN, as well as the transmission of audio, video and data. Unlike the PSTN, the Internet is generally a xe2x80x9cconnectionlessxe2x80x9d network that does not require a bearer channel to be established between a sender and receiver before any messages are transmitted. Because the protocols defined by ISUP depend on bearer channel control signaling to establish such channels between network-nodes, ISUP is not generally suited for controlling the transmission of data between Internet nodes, such as media gateways.
Because it is desired to further converge conventional connection-oriented communications networks, such as the PSTN, with connectionless packet-switched networks, such as the Internet, there is a need in the art for systems and methods that allow connection-oriented protocols to control the routing of data through connectionless networks. In particular, there is a need in the art for methods of adapting the use of ISUP to control the routing of data between media gateways associated with a packet-switched network, such as the public Internet. Preferably, such methods should be transparent to the control network that utilizes ISUP; i.e., no modifications to the standard ISUP protocols should be required.
To address the above-discussed deficiencies of the prior art, the present invention relates to a media gateway (MGW), and methods relating thereto, for controlling the routing of data packets through a xe2x80x9cconnectionlessxe2x80x9d packet-switched network, without bearer channel control signaling. In general, a MGW is operative to receive a connection request associated with a remote MGW, wherein the connection request includes a source address associated with the remote MGW; the MGW defines and stores an association between the source address associated with the remote MGW and a particular port address of the MGW in a mapping table. Subsequently, when the MGW receives a broadcast message that includes an unknown destination indicator, it queries the mapping table using the source address of the broadcast message. If the source address of the broadcast message is found in the mapping table, the MGW retrieves the address associated with the MGW that is mapped to that source address and routes the broadcast message to that address. In this manner, data packets can be communicated through the MGW without the remote MGW knowing the address associated with the MGW.
In exemplary embodiments, the source address includes an Internet Protocol (IP) address of the remote MGW and a port address associated therewith, such as a User Datagram Protocol (UDP) port designator. In order to route data packets through the MGW, when the remote MGW does not provide a particular UDP port address at the MGW, an association is defined between the source address and a particular port address of the MGW; this association can be stored in a port mapping table. When a broadcast message including an unknown destination indicator is received at the MGW, the port mapping table is queried using the source address of the broadcast message to determine a particular port address associated with the MGW, if any, and the broadcast message is then routed to the particular port address. The MGW can then send a message to the source MGW to inform it of the particular port address to which subsequent data packets can be sent, thereby eliminating any further need for the source MGW to send such data packets using broadcast messages.
The connection request can be received by a controller associated with the second MGW from a controller associated with the remote MGW. In a specific embodiment described hereinafter, the packet-switched network utilizes Internet Protocol (IP) addressing for the MGWs; the controllers associated with the MGWs, however, communicate using Integrated Services Digital Network User Part (ISUP) protocols and each controller communicates with its associated MGW using a Gateway Control Protocol (GCP). In such embodiments, the process of transmitting a xe2x80x9cconnection requestxe2x80x9d to a MGW includes the steps of: 1) transmitting an ISUP Initial Address Message (IAM) from a first controller associated with a first MGW to a second controller associated with a second MGW; the IAM includes a source address for the data packets at the first MGW; and, 2) sending a resource allocation message from the second controller to the second MGW. The resource allocation message includes the source address for the data packets.
To facilitate the use of the methods disclosed herein, an exemplary MGW is also disclosed. In an exemplary embodiment, a media gateway adapted to use the methods is operative to: 1) receive a resource allocation message from a controller associated with the MGW, the resource allocation message including a source address for data packets; 2) define and store an association between the address associated with the remote MGW and an address associated with the MGW; 3) receive a broadcast message at the MGW, the broadcast message including a source address; 4) if the broadcast message includes an unknown destination indicator, query the mapping table using the source address of the broadcast message; 5) if the source address of the broadcast message is found in the mapping table, retrieve the address associated with the MGW that is mapped to the source address; and, 6) route the broadcast message to the address associated with the MGW, whereby the broadcast message is communicated through the MGW without the remote MGW knowing the address associated with the MGW. The MGW can then send a message to the source MGW to inform it of the particular port address to which subsequent data packets can be sent, thereby eliminating any further need for the source MGW to send such data packets using broadcast messages.
The methods disclosed herein, and MGWs adapted to employ such methods, are preferably implemented using software-definable processes that can be executed by general or specific purpose computer systems. Those skilled in the art are familiar with the implementation of such processes using software, hardware, firmware, or a combination thereof. The principles of the present invention are not limited to any specific implementation thereof, and all such embodiments are intended to be within the scope of the claims recited hereinafter.
The foregoing has outlined, rather broadly, the principles of the present invention so that those skilled in the art may better understand the detailed description of the exemplary embodiments that follow. Those skilled in the art should appreciate that they can readily use the disclosed conception and exemplary embodiments as a basis for designing or modifying other structures and methods for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.